fix(backend): fix handling of invalid urls in user profile

[eternal-flame-AD]

What

Fix #15634

Why

Additional info (optional)

Checklist

• Read the contribution guide
• Test working in a local environment
• (If needed) Update CHANGELOG.md
• (No infrastructure for this?) Add tests

[github-actions]

このPRによるapi.jsonの差分
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[codecov]

Codecov Report

Attention: Patch coverage is 0% with 18 lines in your changes missing coverage. Please review.

Project coverage is 41.95%. Comparing base (69eee9f) to head (ea798e1).
Report is 6 commits behind head on develop.

Files with missing lines	Patch %	Lines
.../backend/src/core/activitypub/ApRendererService.ts	0.00%	18 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           develop   #15635       +/-   ##
============================================
+ Coverage    15.35%   41.95%   +26.60%     
============================================
  Files          785     1623      +838     
  Lines        72098   165791    +93693     
  Branches      1279     4123     +2844     
============================================
+ Hits         11070    69561    +58491     
- Misses       60604    95753    +35149     
- Partials       424      477       +53     

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[mi-gh-maintainer]

Thank you 🙏